Early 19th century; earliest use found in Leitch Ritchie (1800–1865), novelist and journalist. Apparently imitative of the sound and movement of the waves.
Definition of jobble in US English:
jobble
nounˈdʒɒbl
An agitated movement of water; = "jabble".
Origin
Early 19th century; earliest use found in Leitch Ritchie (1800–1865), novelist and journalist. Apparently imitative of the sound and movement of the waves.